The Collaborative Observational Study of Myopia in COMET Children (COSMICC) is a longitudinal study that has followed the cohort of children who participated in the Correction of Myopia Evaluation Trial (COMET. Currently, at an average age of 17 years, myopia has stopped progressing in only 42% of the subjects in this cohort. This group of ethnically diverse myopic subjects has 7-8 years of standardized, reliable measurements of refractive error and ocular components, with outstanding retention of 93%. Thus, this cohort provides a unique opportunity to characterize progression and stabilization of myopia and to learn how they are influenced by genetic and environmental factors identified from COMET and from the literature. By studying this cohort for an additional 5 years, COSMICC2 seeks to accomplish the following aims. Aim 1: To use the Gompertz and other functions to characterize the course of myopia in the 58% of the COSMICC cohort with progressing myopia and to develop predictive models based on previously identified, intrinsic risk factors (age, ethnicity, and parental myopia). We expect to find that myopia stabilization determined from Gompertz functions fit to the data will be comparable to stabilization using a clinical definition and that results for axial elongation will be similar to those for myopia progression. Aim 2: To test 4 hypotheses related to environmental risk factors for myopia progression and stabilization in this well-characterized cohort of myopes Aim 3: To test 3 hypotheses related to the association of IOP, CCT, and macular thickness with changes in axial elongation and myopia progression in COSMICC subjects This application seeks continued support for the activities of the Coordinating Center, which has successfully served in this role since COMET began and will remain similar to COSMICC. The major responsibilities of the Coordinating Center are to: 1) provide epidemiologic and biostatistical expertise to the design, conduct and analysis of COSMICC2;2) develop and implement the statistical analysis plan;3) collaborate in the development, modification and distribution of forms, documents and protocols;4) be responsible for data management;processing and analysis;5) prepare reports to monitor recruitment, data collection, and data quality;6) coordinate and document communications among clinical centers;7) be responsible for quality assurance procedures;and 8) collaborate in preparing publications of the results. Additional new aims for COSMICC2 are to process and analyze data concerning new measurements of IOP, CCT and macular thickness and volume as they relate to myopia and axial length. Separate applications have been submitted by the Study Chair and each of the 4 clinical centers.